Gear-pump and the like.



C. A. SMITH.

GEAR PUMP AND THE LIKE.

APPLICATIGN FILED OCT. l1. 1917.

1,285,819. Patentemv. 26,1918.

UNITED sTATEs PATENT OFFICE.

CHARLES A. SMITH, F HOPEDALE, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO HOPEDALE MANUFACTURING COMPANY, OF MILFORD, MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS.

GEAR-PUMP AND THE LIKE.

Specieation of Letters-Patent.

Patented Nov. 26, 1e18.

Application med october 11, 1917. serial No. 196,045.

To all whom 'it may concern Be itknown that I, CHARLES A. SMITH, a citizen of the United States, residing at Hoped'ale, in the county of Worcesterand State of Massachusetts. have invented an Improvement in Gear-Pumps and the like, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

The invention hereinafter described relates to gear pumps and other rotary engines, and among other objects provides simple and effective means for compensating for wear on the parts thereof and increasing their etliciency.

These and' other objects of the invention will be more fully described in the following description of one good form of means shown in the accompanying drawings for carrying the invention into practical effect, it being understood that the invention in its true scope is not limited to the details thereof, but as defined-by the appended claims.

In the drawings Figure 1 is a vertical section through a gearA pump shown herein to illustrate the invention;

Fig. 2 is a vertical transverse section taken on the broken line 2 2; and

Fig. 3 is a vertical transverse section taken on the broken line 3-7-3 of Fig. 1.

Referring to the drawings z-The gear pump shown thereiny as embodying the invention comprises a casing having a body 1 and a head 3 detachably connected tosaid body by screws 4.

A pair of intermeshing gears 5 and 6 are mounted in said casing, the latter being formed to present an elliptic-like chamber? having its upper and lower ends curved on a radius corresponding to the radius of said gears, the construction being such that the gears will have a close rotary contact with the curved ends of said chamber.

The casing may have an inlet 9 communicating with a supply pipe 11`connected to a boss 13 of the casing, and the casing may have an outlet 16 communicating with a 'discharge pipe connected toa boss 17 on the casing.

The constructionis such that as the gears revolve in the directions indicated by the arrows, the spaces 18 between the teeth of the gears will coperate with theA curved ends of the chamber to exhaust air from the inlet and feed pipe. When the air is sufliciently exhausted, atmospheric pressure will force theliquid from the feed pipe into the pump casing. The liquid then ills the spaces between/the gears and is carried around and dellvered thereby to the outlet and discharge plpe.

Y To produce a constant pressure of discharge, a by-pass between the inlet and outlet may be provided comprising vertical ports 19 and 21 extending downward from said inlet and outlet respectively, and communicating with a horizontal port 23 in said casing beneath said chamber. This horizontal port may be reduced intermediate its ends and presenta valve-seat 27. A ballvalve 29 is urged toward said seat by ahelical spring 31 Aconfined between said ballvalve and a plug 33 closing one end of said horizontal port` the opposite end of said port being closed by a similar plug 35.

- If the pressure tends to build up at the outlet the liquid will pass back from said outlet into the by-pass, forcing the ballvalve from its seat, and passing thence from the by-pass to the inlet.

In the operation of gear-pumps, the principal wear comes upon the end faces of the gears and the walls engaged-thereby. Next will be described-means for preventing en d play of the gears and for compensating for wear on the parts referred to.

To accomplish this, in the present inand the end 41 of the lower gear projects outward beyond the corresponding end 41 of the upper gear.

The outwardly projecting ends 37 and 41 extend into recesses 47 of a diameter corresponding to the diameter of said gears.

The recess for the upper gear may be formed in the body of the -ca sing while the recess for the lower gear may be formed in the head of the casing.

Suitable movable members may be mounted in said recesses and be adapted to engage the ends of said gears to prevent end play and to take up the wear on the parts. In the present instance of the invention, these members are in the form of collars 49 fitting said recesses and having stems 61 projecting outward in counterbores 53 in said casing and head. To press said collars automatically towardsaid gears they may be provided with helical springs 55 encircling reduced ends 57 of said stems and confined betweenV shoulders of said stems and caps 59 threaded to the outer ends of said counterbores. To prevent rotation of said stems screw keys 51 may be tapped into said head and casing and have reduced ends projecting into grooves 63 in said stems.

The upper gear may be rovided with stud shafts 65 journaled in earings in its spring-pressed collar and the head of said casing. The lower gear may be provided with a stud shaft 67 and a shaft 68jour naled in bearings in its spring-pressed collar and casing respectively. The shaft 68 projects outward lbeyond the casing to receive a driving pulley 69. To prevent leakage from the casing along said shaft it may be provided with a stuiing box comprising suitable packing and a gland 7l secured to the casing by suitable screws, (not shown).

Since the gears have oifset end faces, the

-springpressed collars may completely cover said faces without limitation or interference from the other end faces of the gears and will be able to move in said recesses to take up end play of the gears and compensate for wear on the end faces of the gears and the walls engaged thereby. In the present instance of the invention this movement of the collars is accomplished automatically by the springs acting thereon.

ln use, the gears may wear different amounts, but the construction is such that the wear on each gear may be taken up independently of the other and thus no opportunity for end play is left on either gear.

The by-pass and valve 29 are not indispensable, since excess pressure built up at the outlet may force the members 49 axially outward against the resistance of their springs, away from the ends of the pump gears, and permit the Huid to pass between said members and ends toward the inlet, thereby relieving the excess pressure. The springs, however, are stiff enough to prevent the members from moving from said ends under normal pressure, and consequently,

prevent leakage between them at such times.

It will be understood that the invention is not limited to gear pumps, but that it is applicable to eccentric pumps and other embodiments of rotary engines.

What is claimed is 1. A device of the character described,l comprising. in combination, a casing having curved walls, intermeshing gears fitting said curved walls and axially offset relatively to one another so that an end of each projects beyond the corresponding end of the other, follower members for engagement with the projecting ends of said gears and covering the ends of the teeth and the spaces between the teeth at the projecting ends of the gears, and means tending to press said follower' members against the ends of said gears automatically t0 take up wear and prevent leakage at the ends of the teeth of said gears.

2. A device of the character described, comprising. in combination, a casing having curved walls, interrneshing gears fitting said curved walls and axially offset relatively to one another so that an end of each projects beyond the corresponding end of the other, follower members having areas sufficient to cover the ends of the teeth and the spaces therebetween the projecting ends of the gears, and spring means acting on said follower members for pressing the same against the ends of said gears.

3. A device of the character described. comprising. in combination, a casing, intermeshing gears therein axially offset relativeljf.7 to one another so that an end of each .projects bevond the corresponding end of the other. follower members for engagement with the projecting ends of said gears and at least equal to the diameters of said gears, said members being adjustable to take up wear between the ends of the gears and the surfaces engaged thereby, and means to drive one of said gears.

4:. A device of the character described, comprising, in combination. a casing, intermeshing gears therein axially oifset relatively to one another so that an end of each projects bevond the corresponding end of 'the other, follower members having collars for engagement with the projecting ends of said gears and at least equal to the diameters of said gears. and springl means for pressing said collars toward said projecting ends to maintain a close working fit between them.

5. A device of the character described, comprising, in combination. a casing, intermeshing gears therein axially offset. relatively to one another so that an end of each projects beyond the corresponding end of the other, follower members at least equal to the diameters of said gears and having bearings therein, shafts for said gears journaled in said bearings. and means for adjustf ing said followers along said shafts into intimate working engagement with said pro bers, removable closures for said chambers, and springs confined between said closures and follower members for pressing the latter toward said gears. i

7. A device of the character described, comprising, in combination, a casino' having a body and a head, means detachfbly connecting said head to said body, intermeshing gears 1n said casing axially offset relatively to one another so that an end of each projects beyond the corresponding end of the other, follower members for engagement with the projecting ends of said gears and of areas sufficient to cover ends of the teeth of said gears, one of said follower members being mounted in the casing body, and the other follower member being mounted in said head, and springs actmg on said follower members for presslng the same into intimate engagement with the projecting ends of the gears to prevent leakage between the parts.

`8. A device of the character described, comprising, in combination, a casing having an inlet and an outlet, intermeshing gears mounted in said casing for feeding fluid from said inlet to said outlet, said gears being axially offset relatively to `one another, so that an end of each -projects beyond the corresponding end of the other, follower members coverin the ends of the teeth at the projecting ends of said gears, and means tending continuously to press said follower members against said projecting ends to prevent leakage between said inlet and outletl around the paths of rotation of said gears.

9. A device of the character described, comprising, in combination, a casing having an inlet and an outlet, a pair of intermeshing gears -mounted in said casing for feeding fluid from said inlet to said outlet, said gears being axially offset relatively to one another so that an end of each projects beyond the corresponding end of another, said casing having a by-pass connecting said inlet and outlet, valve means for said by-pass to relieve pressure at said outlet, follower mem bers for engagement with the projecting ends of said gears, and at least equal to the diameters of said gears, spring means for pressing said follower members toward the projecting ends of said gears, and means for driving one of said gears.

In testimony whereof, I have signed my name to this specification.

CHARLES A.' SMITH, 

